Torsion bar

[pawanhv]

Hi I am currently trying to understand the effect of cross section on the torsional resistance of the bar/rod. I know that the moment about XX axis refers to the bending resistance . But I am confused,in case of torsion is it the moment along ZZ which has to be considered or the torsion constant ? I have no idea. I heard Izz can simply be sum of Ixx and Iyy for a tube of circular cross section . But what about open cross sections like C. I have a complicated cross section and I want to compare it with other cross sections . can you guide me ?

 

[structSU10]

Torsional response has a lot to do with section geometry. You need the torsional constant J, and, if applicable, the warping factor Cw. AISC design guide 9 has some general information on torsional analysis.

If you have a complicated shape, there are some programs out there, both free and paid, that can calculate torsional properties of the cross-section, which could help with any stress check you must do.

 

[desertfox]

Hi pawanhv

Can you provide a sketch of your section.

 

[pawanhv]

Hi structSU10 , thanks for your reply. I will refer the book you recommended and ask if i get any questions, but i noticed it is for steel structures, will it be valid for plastic structures too?

hi desertfox, thanks for your reply too, I will try and sketch a profile to post it here maybe tomorrow .

 

[pawanhv]

Hi,
can you give me a name of the software that can calculate torsion properties for my section pls? and is it possible to calculate if the section has an insert of differnt properties? thanks

 

[structSU10]

See this thread

http://www.eng-tips.com/viewthread.cfm?qid=328480

It discusses programs for section property analysis.

And with a composite, shear flow at the interface would be an important consideration.

 

[johnbridge231]

Regarding cross section calculations, this software might be useful to you.
Regards.

 

[ChrisMagadiaCom]

torsional global resistance is more to do with geometric properties although flexural rebars if placed appropriately along the cross section area will increase its sectional torsional moment of resistance

http://www.chrismagadia.com

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